Cattell's own words when giving the meaning of "personality" are that personality is

“That which tells us what a person will do when placed in a given situation.”

The core principle of the Structure-based systems theory is that personality is a product of the interaction of our attributes, or traits, and the environment that produces the support systems that build and mold us.

In other words, our characteristics will determine the choices that we make in order to interact with the world around us. Cattell defines ability traits as the tools that equip us to deal with everyday problems. As each person is different, some individuals will be better equipped than others to deal with everyday life.

According to Cattell, pathological behavior is the product of the current environment. If our society is in chaos and crisis, there will be higher chances of individuals developing the pathological behavior that they acquire through social learning. This concept, according to Cattell, is called "Beyondism" and has been studied scientifically to correlate current events to behavioral trends and patterns. A way to support Cattell's view is to compare how as our society becomes more chaotic, the crime rate increases as well as the incidence of mental illness. Hence, the circumstances "cause" the individual the way that the individual causes them as well.